
import java.lang.Math;
import java.io.*;
public class Main{
public static void main(String[]args) {
	double v,r;
	String a="";
	try{
		BufferedReader in=new BufferedReader(new InputStreamReader(System.in));
		a=in.readLine();
	}catch(IOException e){System.out.println("程序有错！");}
	
	r=Double.parseDouble(a);
	v=(4/3.0)*Math.PI*r*r*r;
	System.out.println("V="+v);
}
}
